The mean number of hours per day spent on the phone, according to a national survey, is four hours, with a standard deviation of two hours. If each time was increased by one hour, what would be the new mean and standard deviation? (2 points)

Select one:
a. 4, 2
b. 4, 3
c. 5, 2
d. 5, 3

The new mean is 5.

The new standard deviation is also 2.

Step-by-step explanation:

Let the sample space of hours be as follows, S = {x₁, x₂, x₃...xₙ}

The mean of this sample is 4. That is,

The standard deviation of this sample is 2. That is, .

Now it is stated that each of the sample values was increased by 1 hour.

The new sample is: S = {x₁ + 1, x₂ + 1, x₃ + 1...xₙ + 1}

Compute the mean of this sample as follows:

The new mean is 5.

Compute the standard deviation of this sample as follows:

The new standard deviation is also 2.

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

answer:

f(5/2) = 10/3

i hope this you!

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step-by-step explanation: